【摘要】 本文描述了产于自贡大山铺中侏罗世沙溪庙组下部的似哺乳爬行动物中三列齿兽科-新属种——川南多齿兽(Polistodon Chuannanensis,gen.et sp.nov.)。新属新种与云南卞氏兽比较相似。其最突出的特点是上颊齿数特多,达到13颗。每颗上颊齿齿尖数少,外、中、内三行均为二个齿尖。更多还原

【Abstract】 Some well preserved tritylodont remains which include a skull, mandibleand a small number of post--cranial bones have been discovered in the MiddleJurassic dinosaurian fauna from Dashanpu, Zigong, Sichuan. We named thesespecimens as Polistodon chuannanensis (gen. et sp. nov.). The skull is slightlydamaged though strongly distorted. In general, the form and elements of theskull are similar to those of Bienotherium yunnanense Young, but the most markedfeatures of Polistodon, which are distinguished from Bienotherium and other alliedgenera in the Tritylodontidae are as follows: Sagital crest low and short,zygomatic arch expansion not pronounced, and its posterior end obviouslyhigher than anterior end. The angular process and "articular process" of lowerjaw clearly differentiated. Dental formula is 1. 0. 13 / 2. 0. 7--8 with onlyone upper incisor in each side and 13 upper cheek teeth (postcanines), inwhich the last one not in function. The anterior cheek teeth both of upperand lower jaw completely molarized. The cusp formula of upper cheek teeth2·2·2·.2 lower incisors in each side, 8 lwer cheek teeth in right side and 7in left side, the cusp formula 2.2.更多还原